1. Field of the Invention
The present invention relates to a method and apparatus for laying a traffic calming surface which will alert vehicle drivers to hazards ahead by creating an audible and vibratory warning inside the vehicle.
2. Description of the Related Art
A number of traffic calming surfaces have been developed in order to alert drivers to approaching hazards, such as a junction or a pedestrian crossing, and serve to indicate to the driver that he should decelerate. Speed bumps have been widely used for a number of years and comprise a raised section which extends transversely relative to the intended direction of travel. In order to traverse the speed bump smoothly and safely, the speed of a vehicle must be reduced. A series of speed bumps positioned along a stretch of road will serve to ensure that the speed of vehicles moving along the road are regulated.
In more recent years, rumble areas/strips have been employed, particularly in rural areas, in an attempt to slow traffic approaching a potentially hazardous situation. The known rumble strips generally comprise a concrete, bituminous or synthetic surface overlay having a series of irregularities such as raised bars or an imprinted pattern of grooves. As a vehicle traverses the rumble strip, a range of vibrational frequencies are generated at the tyres which will be transmitted to the driver's cab. The vibrational effect of the strip will be felt and heard by the driver and will act as a warning that the driver should reduce his speed.
There are a number of techniques for laying these surfaces which involve, for example, a means for pressing a series of ribs onto the road surface, or embossing processes which comprise laying a molten material and impressing a pattern of grooves into the upper surface of the material.
Rumble strips were originally developed in the 1970's as a traffic calming surface for use primarily in rural areas. At that time, little thought was given to the external noise disturbance generated as vehicles traversed the strips when the surface was designed. One of the main disadvantages of the rumble strips currently employed on the roads is that they generate considerable noise levels outside the vehicle which has a detrimental effect on the surrounding environment. This problem is compounded by increasing traffic volumes seen on the roads today. For these reasons, the environmental effects of introducing traffic calming surfaces into urban, residential and rural areas has become an issue. As a result of pressure imposed on Governments and local authorities by environmental agencies, there has been a considerable need to provide a means to slow traffic approaching hazardous areas, while minimising the consequential noise disturbance which may be experienced in the surrounding area. More recently, urban planners have also become interested in the need to develop a quieter means of controlling traffic.